Semiconductor device and method of manufacturing the same

Patent metadata

Field	Value
Publication number	US-9985039-B2
Application number	US-201715664474-A
Country	US
Kind code	B2
Filing date	Jul 31, 2017
Priority date	Aug 24, 2015
Publication date	May 29, 2018
Grant date	May 29, 2018

Abstract

An insulating film made of the same material as that of a gate insulating film is formed so as to cover one sidewall of a control gate on a conducting film for floating gate. By selectively removing the conducting film for floating gate with the insulating film as a mask, a floating gate is formed from the conducting film for floating gate, and a portion of the gate insulating film is exposed at the floating gate. A nitrogen introduced portion is formed by introducing nitrogen into the exposed portion of the gate insulating film. Then, the insulating film is removed to expose an upper surface of a lateral protrusion of the floating gate. An erase gate is formed so as to face the upper surface and a side surface of the lateral protrusion.

First claim

What is claimed is:

1. A semiconductor device comprising:
a semiconductor substrate having a main surface;
a gate insulating film formed on the main surface of the semiconductor substrate;
a floating gate formed on the gate insulating film;
a control gate formed on the floating gate with a first insulating film interposed therebetween; and
an erase gate formed on the main surface,
the floating gate including a lateral protrusion protruding laterally from a region immediately below the control gate,
the erase gate being formed so as to face the lateral protrusion,
the gate insulating film including a first gate insulating portion located between the semiconductor substrate and the floating gate, and a second gate insulating portion located between the semiconductor substrate and the erase gate,
the second gate insulating portion having a portion made of a material different from that of the first gate insulating portion.

2. The semiconductor device according to claim 1 , wherein
the first gate insulating portion includes a portion made of silicon oxide, and the second gate insulating portion includes a portion made of silicon oxynitride.

3. The semiconductor device according to claim 1 , further comprising a select gate formed on the main surface of the semiconductor substrate, wherein
the gate insulating film includes a third gate insulating portion located between the semiconductor substrate and the select gate, and
the third gate insulating portion has a portion made of a material different from that of the first gate insulating portion.

4. The semiconductor device according to claim 3 , wherein
the third gate insulating portion includes a portion made of silicon oxynitride.

Assignees

• Renesas Electronics Corp

Inventors

• Kodama Satoshi
• Hasegawa Eiji

Classifications

• H01L27/11521 Primary

  Electricity · mapped topic

• H01L29/42328

  Electricity · mapped topic

• H10D64/035

  comprising conductor-insulator-conductor-insulator-semiconductor structures · CPC title

• H10D30/6892 Primary

  having at least one additional gate other than the floating gate and the control gate, e.g. program gate, erase gate or select gate · CPC title

• H10B41/35

  with a cell select transistor, e.g. NAND · CPC title